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Abstract

White spot syndrome virus (WSSV) is one of the most prevalent and lethal viruses for shrimp, and oral administration of VP28 is a promising approach to protect shrimp against WSSV. Although seven heterologous expression systems have been successful since 2004, no one has been commercialized in shrimp industry. This paper presented the idea of “both drug and feed from the same feedstock” to develop oral vaccine against WSSV. Filamentous, heterocystous cyanobacterium, Anabaena sp. PCC 7120, was used to express major envelope protein, VP28, for feeding post larvae of shrimp. The expression of vp28 gene in transgenic mutant was analyzed by Western blotting and real-time quantitative polymerase chain reaction (RT-qPCR). For vaccination, Litopenaeus vannamei was orally administrated by feeding the wild type and mutants of Anabaena cells for 10 days, and was challenged with WSSV during 10 days post vaccination. The post larvae were fed with the mutant harboring vp28 (10 μg shrimp⁻1). The post larvae were divided five groups and their survivals were as follows: (1) negative control (neither vaccination nor challenge), 100%; (2) positive control (challenge and no vaccination), 0%; (3) feeding the wild type, 15.5%; (4) feeding blank, 20.6%; and (5) feeding the mutant harboring vp28, 68.0%. Moreover, the post larvae fed the mutant harboring vp28 grew better than no feed. Also, the photosynthetic features indicated the transgenic mutant was easier to cultivate. These data show that transgenic mutant harboring vp28 was favorable not only to use both for drug and feed but also to cultivate in scale.